Quark Flavor PhysicsJoel Butler, Zoltan Ligeti, Jack Ritchie

• Introduction & IF Workshop report

• Status: sizable new physics allowed

• Key measurements, opportunities, conclusions

http://www.ph.utexas.edu/quarkflavor

2011 – 2012 IF Workshop activities

• Heavy Quarks Working Group:

http://www.ph.utexas.edu/˜heavyquark

• Contacted world-wide all relevant experimental groups + many theorists

• Solicited and received written contributions from many experiemnts (13)

Solicited and received inputs from many theorists (7)

• 1.5 days of well-attended sessions at Rockville on B, K, and charm physics

Covered theory, experiment, detector, accelerator advances + lots of discussions

• Report has 67 authors, went through several iterations

ZL — p.1

Experimental input specifically for IF Workshop

• NA62: Ultra Rare Kaon Decays (K+ → π+νν at CERN)

KOTO: The KOTO Experiment at J-PARC

The TREK Program at J-PARC

Measuring K+ → π+νν at Fermilab, The ORKA Collaboration

Measuring K0L → π0νν at Project X, Bryman and Littenberg

• LHCb: Physics opportunities with LHCb and its planned upgrade

SuperB Report for Intensity Frontier Workshop

The Physics of the SuperKEKB/Belle II Super Flavor Factory

CMS Prospects for Heavy Flavor Physics

• BES-III: Overview of the Key BES-III Physics Opportunities

TAPAS: Heavy Quark Physics at the Antiproton Intensity Frontier

Liquid Argon TPC as a means to study rare mu and K decays , Cline and Lee

• Also considered ∼20 recent physics & technical reports (∼3000 pages, ∼200 MB)

ZL — p.2

Discussed even more experiments

1.) KLOE-2, NA62, KOTO, TREK, ORKA, Project-X opportunities

2.) Belle-II at SuperKEKB, SuperB in Italy, LHCb and upgrades, CMS, ATLAS

3.) BES III, and charm capabilities of 2.) above

• Theorists’ inputs:“A Letter from the Energy Frontier to the Intensity Frontier,” Sundrum

“Benchmarks in Quark Flavor Physics,” Blanke

“The Need to Advance the Intensity Frontier,” Zupan

“The Future Quark Flavor Physics Program,” Van de Water, Kronfeld, Mackenzie, Sharpe

“Lattice QCD and High-Intensity Flavor Physics,” USQCD Collaboration

“Kaon Physics: Looking Beyond the Standard Model,” Christ and Soni

“B → V V and B → V `+`− Angular Analysis,” Datta and Duraisamy

ZL — p.3

Discussions at Rockville

• Allocated time between talks + additional 3 hours of discussions / brainstorming

With moderators and fairly provocative questions...

– Complementarity / redundancy / necessity? Strong and specific motivations?

– What are the most important theoretical issues?

– Any quantitative metrics to compare measurements of different processes?

– Are there enough cross checks in the currently planned program?– Is one measurement of key modes enough?

– What do we learn from “new” QQ states?

– What would be lost without US program / US participation?

– What accelerator R&D is needed? What facilities are needed?

ZL — p.4

“Heavy Quarks” — IF Workshop report

• Table of contents:

1. Quark Flavor as a Tool for Discovery

2. Strange, Charm, and Bottom Quarks as probes of New Physics

2.1 K Decays

2.2 B and Bs Decays

2.3 D Decays

2.4 Effective Theories, Hadronic Physics, and Exotic States

3. A World-wide Program of Quark Flavor Experiments

3.1 Kaon Experiments

3.2 B-meson Experiments

3.3 Charm Experiments

3.4 Exotic States

4. The Need for New Experiments and Facilities

ZL — p.5

(Preliminary) plans for “Snowmass”

• We want your input, but please look at report before telling us what to do

Major changes since IF report? Something forgotten? New boundary conditions?

• Past planning:Jim Siegrist yesterday: “Stringing together projects that build upon previous investments either

scientifically or through recycling of infrastructure is generally well received.”

Practically the opposite was done in flavor physics in the US: world leadingK andB experiments

abandoned / not pursued, while other regions are charging ahead — Can the US recover?

• Future planning: Clear physics case, how to make it more crisp / compelling to non-experts?

– The interesting messages are not simple to explain [Not just one critical measurement; theory can be complicated]

– The simple messages are not interesting [Lincoln Wolfenstein doesn’t care what ρ and η are, so why should you?]

• Exciting flavor physics projects in Europe & Asia; US has an opportunity in Kaons

Interpretation of “situation analysis” — “decision tree” — “pilot studies” for us? [Siegrist]

ZL — p.6

The big picture

Experiments and energy scales

1 3 5 7 9 11 13 15 17

Tevatron

proton decay

flavor (quarks)

Experimental reach (with significant simplifying assumptions)

log(Energy[GeV])

LHC

dark matter

mu to e

neutrino propertiesE

WS

B

see−

saw

GU

T

Pla

nck

Dashed arrows show anticipated improvements in next generation of experiments

• Goal: Higher energy — Shorter distances — Earlier in the Universe

Goal: Energy, Intensity, Cosmic frontiers all address these in different and complementary ways

Energy frontier: accelerator energy gives upper limit on mass of new particles produced

Intensity frontier: very heavy particles can affect the measurements via quantum effects

ZL — p.7

Experiments and energy scales

1 3 5 7 9 11 13 15 17

Tevatron

proton decay

flavor (quarks)

Experimental reach (with significant simplifying assumptions)

log(Energy[GeV])

LHC

dark matter

mu to e

neutrino propertiesE

WS

B

see−

saw

GU

T

Pla

nck

Dashed arrows show anticipated improvements in next generation of experiments

– proton decay already ruled out simplest version of grand unification

– neutrino experiments hope to probe see-saw mechanism

– flavor physics is getting to the level that even suppressed TeV-scale physics could show up

– LHC was in a unique situation that a discovery was virtually guaranteed (known since the 80’s)

ZL — p.7

Can do or cannot do?

⇒ Cronin & Fitch, Nobel Prize, 1980

⇒ 3 generations, Kobayashi & Maskawa, Nobel Prize, 2008

Spectacular track record

• Uncertainty principle ⇒ heavy particles, which cannot be produced, affect lowerenergy processes (typically suppressed byE2/M2) ⇒ can probe very high scales

– εK predicted 3rd generation (Kobayashi & Maskawa)

– Absence of KL → µµ predicted charm (Glashow, Iliopoulos, Maiani)

– ∆mK predicted mc (Gaillard & Lee)

– ∆mB predicted large mt

• Were critical to develop the SM, probably crucial to understand LHC physics, too

• Flavor physics and CP violation are excellent probes of BSM physics

• Already learned that TeV-scale NP must have very special features — flavor hasmainly been an input to model building (structures imposed to satisfy bounds)

ZL — p.8

Flavor physics — the modern view

• “Flavor physics”: what breaks U(3)Q × U(3)u × U(3)d → U(1)Baryon ?

• SM flavor problem: hierarchy of masses and mixing angles; why ν’s are different

• NP flavor problem: TeV scale (hierarchy problem) � flavor & CPV scale

εK:(sd)2

Λ2⇒ Λ>∼10

4TeV, ∆mB:

(bd)2

Λ2⇒ Λ>∼10

3TeV, ∆mBs:

(bs)2

Λ2⇒ Λ>∼10

2TeV

– Most TeV-scale new physics models have new sources of CP and flavor viola-tion, which may be observable in flavor physics but not directly at the LHC

– The observed baryon asymmetry of the Universe requires CPV beyond the SM(Not necessarily in flavor changing processes, nor necessarily in quark sector)

– Hope: new source of symmetry violation⇒ new interactions / particles

• Flavor sector can be tested a lot better, many NP models have observable effects

ZL — p.9

Current status: CKM fit in the SM

• Past: Ten years ago we did not know that theCKM picture was (essentially) correct

O(1) deviations / modifications were possible

• There are no significant deviations from SM,a number of tensions, many measurementswhere huge improvements are possible

• Allowed region is much larger using only tree-level information γ and |Vub|

γ

γ

α

α

dm∆

Kε

Kε

sm∆ & dm∆

ubV

βsin 2

(excl. at CL > 0.95)

< 0βsol. w/ cos 2

exc

luded a

t CL >

0.9

5

α

βγ

ρ

­1.0 ­0.5 0.0 0.5 1.0 1.5 2.0

η

­1.5

­1.0

­0.5

0.0

0.5

1.0

1.5

excluded area has CL > 0.95

Winter 12

CKMf i t t e r

• This picture makes things look more constrained than they really are; allowing forNP (more flavor parameters) can change the fit completely

• O(20%) NP contributions to most loop processes still possible; is Λflavor � Λweak?

ZL — p.10

Constraints on ∆F = 2 (mixing)

• Bounds with O(1) couplings are in the 102 − 105 TeV range

OperatorBounds on Λ [TeV] (C = 1) Bounds on C (Λ = 1 TeV)

ObservablesRe Im Re Im

(sLγµdL)2 9.8× 102 1.6× 104 9.0× 10−7 3.4× 10−9 ∆mK ; εK

(sR dL)(sLdR) 1.8× 104 3.2× 105 6.9× 10−9 2.6× 10−11 ∆mK ; εK(cLγ

µuL)2 1.2× 103 2.9× 103 5.6× 10−7 1.0× 10−7 ∆mD; |q/p|, φD(cR uL)(cLuR) 6.2× 103 1.5× 104 5.7× 10−8 1.1× 10−8 ∆mD; |q/p|, φD

(bLγµdL)2 5.1× 102 9.3× 102 3.3× 10−6 1.0× 10−6 ∆mBd

; SψKS(bR dL)(bLdR) 1.9× 103 3.6× 103 5.6× 10−7 1.7× 10−7 ∆mBd

; SψKS(bLγ

µsL)2 1.1× 102 2.2× 102 7.6× 10−5 1.7× 10−5 ∆mBs; Sψφ(bR sL)(bLsR) 3.7× 102 7.4× 102 1.3× 10−5 3.0× 10−6 ∆mBs; Sψφ

• Guaranteed to give key information in any scenario — what flavor tells us?

Evidence for BSM?FLAVOR

yes no

ATLAS & CMSyes complementary information distinguish modelsno tells us where to look next flavor is the best telescope

ZL — p.11

The Future

What can flavor physics teach us about BSM physics?

Reasons to seek higher precision

• What are the expected deviations from the SM induced by TeV-scale NP?

Generic flavor structure already ruled out by orders of magnitudes — can find any size deviations

below the current bounds. In a large class of scenarios expect observable deviations.

• What are the theoretical uncertainties?

Highly process dependent — in many key measurements theory uncertainties are smaller than

the expected sensitivity of future experiments.

• What to expect in terms of experimental precision?

Useful data sets will increase by ∼102±1, and will probe fairly generic BSM predictions

• What will the measurements teach us if deviations from the SM are [not] seen?

The new flavor physics data will be complementary with the high-pT part of the LHC program.

The synergy of measurements can teach us about what the new physics at the TeV scale is [not].

• ⇒ Very rich program of measurements & searches

ZL — p.12

K physics

In many NP models, the K constraints are the strongest, since so are the SM suppressions

These are built into all NP models since the 70’s — models constructed to evade the flavor bounds!

Precision tests with kaons

• CPV in K system is at the right level (εK accommodated with O(1) KM phase)

• Hadronic uncertainties preclude precision tests (ε′K notoriously hard to calculate)

We cannot rule out (nor prove) that the measured value of ε′K is dominated by NP(N.B.: bad luck in part — heavy mt enhanced hadronic uncertainties, but helps for B physics)

• With lattice QCD improvements, εK has become more sensitive, hopes for ε′/ε

• K → πνν : Theory error ∼ few %, but very small rates 10−10 (K±), 10−11 (KL)

A ∝

(λ5m2

t) + i(λ5m2t) t : CKM suppressed

(λm2c) + i(λ5m2

c) c : GIM suppressed(λΛ2

QCD) u : GIM suppressed

� �� �

��������� �� ���

� �

� � � �� �

So far O(1) uncertainty in K+ → π+νν, and O(103) in KL → π0νν

• ⇒ Need much more data to achieve ultimate sensitivity

ZL — p.13

The quest for K → πνν

• Long history of ingenious experimental progress (huge backgrounds)

E787/E949: 7 events observed, B(K → π+νν) = (1.73+1.15−1.05)× 10−10

SM: B(K+ → π+νν) = (0.78± 0.08)× 10−10, B(K0L → π0νν) = (0.24± 0.04)× 10−10

CERN NA62: ∼ 100 K+ → π+νν

events in 2012–2016/7

FNAL ORKA proposal: ∼ 1000 K+ →π+νν events [Stage-1 approval]

J-PARC KOTO: observe K0L → π0νν

at SM level

FNAL w/ project-X: proposal for ∼1000 event K0

L → π0νν

ZL — p.14

K → πνν and other measurements

• Very clean: single operator (sd)V (νν)V−A, form factor measured in K → π`ν

One complex param., K+ → π+νν measures |X|, KL → π0νν measures ImX

Rates∝|Vcb|4, drops out from ratio (but then less discriminating power), so want highest precision

Observable SM Theory Current Expt. Future Experiments

B(K+ → π+νν) 7.8× 10−11 1.73+1.15−1.05 × 10−10 ∼10% measurement from NA62

∼5% measurement from ORKA∼2% with Project X

B(K0L → π0νν) 2.43× 10−11 < 2.6× 10−8 1st observation from KOTO

∼5% measurement with Project X

B(K0L → π0e+e−)SD 1.4× 10−11 < 2.8× 10−10 ∼10% measurement with Project X

B(K0L → π0µ+µ−)SD 3.5× 10−11 < 3.8× 10−10 ∼10% measurement with Project X

|PT | in K+ → π0µ+ν ∼ 10−7 < 0.0050 < 0.0003 from TREK< 0.0001 with Project X

RK = Γ(Ke2)/Γ(Kµ2) 2.477× 10−5 (2.488± 0.080)× 10−5 ±0.054× 10−5 from TREK±0.025× 10−5 with Project X

B(K0L → µ±e∓) < 10−25 < 4.7× 10−12 < 2× 10−13 with Project X

ZL — p.15

B physics

Sizable BSM in Bd,s mixing still allowed

• Few notable tensions, otherwise no preference for NP contributions (lots of room)

dh

0.0 0.2 0.4 0.6 0.8 1.0

dσ

0.0

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3.0

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0.1

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0.8

0.9

1.01-CL

excluded area has CL > 0.95

LP 11

CKMf i t t e r

SL, Aντw/o B->

sh0.0 0.5 1.0 1.5 2.0 2.5

sσ

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0.0

0.1

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0.8

0.9

1.0p­value

excluded area has CL > 0.95

LP 11

CKMf i t t e r

M12 = MSM12 (r e2iθ) = MSM

12 (1 + h e2iσ)

• In many cases, we do not yet know if BSM� SM! A must to find out!

• Need a lot more data from LHCb and Super-(KEK-)B, and lattice QCD progress

ZL — p.16

β, βs, α, γ — large improvements possible

sin(2βeff

) ≡ sin(2φe1ff) vs C

CP ≡ -A

CP

Contours give -2∆(ln L) = ∆χ2 = 1, corresponding to 60.7% CL for 2 dof

-0.4 -0.2 0 0.2 0.4 0.6 0.8 1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

sin(2βeff

) ≡ sin(2φe1ff)

CCP ≡ -ACP

φ KS

η′ K0

KS K

S K

S

π0 K

S

ρ0 K

S

ω KS

f0 K

0

f2 K

S

fX

KS

π0 π

0 K

S

π+ π

- K

S NRK

+ K

- K

S

b→ccs

H F A GH F A GMoriond 2012

PRELIMINARY

b

bR

R

~ sR~

s

s

s

s

R,L

R,L

R

R

~(δ23)RR

d_

?

• Key measurements will benefit from 100 timesmore data ⇒ 10 times smaller error

• Will improve bounds on NP substantially [need both LHCb and super-(KEK-)B]

(deg)α

0 20 40 60 80 100 120 140 160 180

p­v

alu

e

0.0

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0.4

0.6

0.8

1.0

CKM12 (prel.)

CKMf i t t e r

(WA)ρρ→B

(WA)ππ→B

(WA)πρ→B

Combined

CKM fit

(deg)γ

0 20 40 60 80 100 120 140 160 180p

­valu

e0.0

0.2

0.4

0.6

0.8

1.0

Winter 12

CKMf i t t e r

Full Frequentist treatment on MC basis

D(*) K(*) GLW + ADS

D(*) K(*) GGSZ Combined

CKM fit

WA

ZL — p.17

Unexpected developments will continue

• Plethora of observables — cannot overestimate value of broad program (DCP )

E.g.: Best α & γ measurements at BaBar/Belle not in previously expected modes

E.g.: Even less expected: “new” QQ and Ds(2317, etc.) narrow states

• Experimentalists & theorists challenge each other ⇒ new ideas / methods (α, γ)

• E.g., B → φKS willget roughly as goodas B → ψKS is now

(b) B0 → φK0

0

20

40

60q=+1q=−1

Ent

ries

/ 2.5

ps

-0.5

0

0.5

-7.5 -5 -2.5 0 2.5 5 7.5-ξfΔt(ps)

Asy

mm

etry

⇒

(d) B0 → J/ψK0

0

100

200

300400 q=+1

q=−1

Ent

ries

/ 0.5

ps

-0.5

0

0.5

-7.5 -5 -2.5 0 2.5 5 7.5-ξfΔt(ps)

Asy

mm

etry

ZL — p.18

Substantial discovery potential in many modes

• Some of the theoret-ically cleanest modes(ν, τ , inclusive) onlypossible at e+e−

• Many modes first seen atsuper-(KEK-)B or LHCb

• In some decay modes,even in 2025:

(Exp. bound)/

SM>∼103

(E.g.: B(s)→τ+τ−, e+e−

unlimited “muddle” building)

[Grossman, ZL, Nir, arXiv:0904.4262,

Prog. Theor. Phys. special issue com-

memorating the KM Nobel Prize]

ZL — p.19

An LHCb best buy list

• LHCb will probe Bs sector at a level comparable to Bd

• The CP asymmetry, SBs→ψφ

• Difference of CP asymmetries, SBs→ψφ − SBs→φφ• Bs → µ+µ− (∝ tan6 β), search for Bd → µ+µ−, other rare / forbidden decays

• 104−5 events in B → K(∗)`+`−, Bs → φγ, . . . — test Dirac structure, BSM op’s

• γ from B → DK and Bs → DsK

• Search for charged lepton flavor violation, τ → 3µ and other modes if possible

• Search for CP violation in D0 −D0 mixing

• [Precisely measure τΛb — affects how much we trust ∆ΓBs calculation, etc.]

• Very broad program, complementary to Super-(KEK-)B

• With large BSM discovery potential

ZL — p.20

A Super-(KEK-)B best buy list

• Include observables: (i) sensitive to different NP, (ii) measurements can improveby an order of magnitude, (iii) not limited by hadronic uncertainties

• Difference of CP asymmetries, SψKS − SφKS• γ from CP asymmetries in tree-level decays vs. γ from SψKS and ∆md/∆ms

• Search for charged lepton flavor violation, τ → µγ, τ → 3µ, and similar modes

• Search for CP violation in D0 −D0 mixing

• CP asymmetry in semileptonic decay (dilepton asymmetry), ASL

• CP asymmetry in the radiative decay, SK∗γ

• Rare decay searches and refinements: b→ sνν, B → τ ν, etc.

• Complementary to LHCb

• Any one of these measurements has the potential to establish new physics

ZL — p.21

charm physics

D0: mixing in up sector

• Complementary to K,B: CPV, FCNC both GIM & CKM suppressed⇒ tiny in SM

– 2007: observation of mixing, now >∼10σ [HFAG combination]

– Only meson mixing generated by down-type quarks(SUSY: up-type squarks)

– SM suppression: ∆mD, ∆ΓD <∼ 10−2 Γ, since doubly-Cabibbo-suppressed and vanish in flavor SU(3) limit

– How small CPV would still unambiguously establishnew physics?

|q/p|

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8

Arg

(q/p

) [d

eg

.]

−60

−40

−20

0

20

40

60

σ 1

σ 2

σ 3

σ 4

σ 5

HFAG-charm

March 2012

Don’t known if |q/p| is near 1!

• Particularly interesting for SUSY: ∆mD and ∆mK ⇒ if first two squark doubletsare within LHC reach, they must be quasi-degenerate (alignment alone not viable)

ZL — p.22

Direct CP violation in D decay?

• LHCb: ∆aCP ≡ aK+K− − aπ+π− = −(8.2± 2.1± 1.1)× 10−3

CDF: ∆aCP = −(6.2± 2.1± 1.0)× 10−3 af ≡Γ(D0 → f)− Γ(D0 → f)

Γ(D0 → f) + Γ(D0 → f)

• World average: ∆aCP = −(6.78± 1.47)× 10−3 (>4σ) [HFAG]

World average: aK+K− = (−2.3± 1.7)× 10−3, aπ+π− = (2.0± 2.2)× 10−3

• Would ∆aCP central value be a sign of NP? (It is beyond all prior SM estimates)

In the SM ∆aCP suppressed by |VcbVub|/|VcsVus| ' 0.07%; however, an enhance-ment, similar to ∆I = 1

2 rule could accommodate the data [Grinstein & Golden, 1989]

How do we tell? Use many measurements... separate asymmetries, etc.

• What kind of new physics could explain it? [many recent papers]

ZL — p.23

Impacts on broader program

• Determination of CKM elements from leptonic and semileptonic modes

• Phases from CP -tagged decays: very useful for B factories (γ)

• Test lattice QCD predictions

• Spectroscopy (charmonia, glueballs, etc.)

• Several experiments will pursue charm physics:

– LHCb and super-(KEK-)B are charm factories

– Dedicated charm experiments: BES III, Panda

ZL — p.24

Final comments

Flavor information useful in all scenarios

• Nima @ Rockville (Nov. 30, 2011):

ZL — p.25

Main points (1)

• Flavor physics is an essential part of the future HEP program

Crucial in all scenarios — whether LHC sees BSM or not:

To understand structure of new interactions / to probe mass scales beyond LHC

• New physics in most FCNC processes may still be ∼20% of the SM or more

• Few hints of discrepancies in SM fit; some (or others) may become decisive

• In many modes, theory is good enough — need high(er) statistics measurements

• Theory will also improve (continuum + lattice), and as larger data sets becomeavailable, interplay between measurements and theory will add to this list

• Enables doing lots of hadronic physics

• This program will address key issues, and provide important complement to LHC

ZL — p.26

Main points (2)

• A rich program of heavy quark experiments is being pursued World-wideSome key processes to search for new physics:

K+ → π+νν and K0L → π0νν aiming at 1000 event level

CP violation in Bs → ψφ

β from b→ ccs vs. from loop-dominated decaysγ and |Vub|— tree-level “reference” to compare NP withBs,d → `+`−, B → `ν, ASL

Many b→ sγ, s`+`−, sνν observables (and s↔ d)

CP violation in D mixing, direct CP violation in charm decays

• Having >1 experiment is very valuable: competition, cross-checks, confirmationEspecially critical if deviations from the SM are seen

• Exploring NP requires LHCb upgrade, super-(KEK-)B, and K experiments

ZL — p.27

Exciting journey ahead

Many opportunities to reveal and constrainnew physics using flavor physics in next decades

[Only way to avoid this: not to carry out the experiments]

Persis @ Rockville: opportunities for paradigm changing scientific advances

Backupl slides

Overconstraining the standard model

dm∆ sm∆ &

dm∆

ubV

α

βγ

ρ

­0.4 ­0.2 0.0 0.2 0.4 0.6 0.8 1.0

η

0.0

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exclu

ded

are

a h

as C

L >

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5

Winter 12

CKMf i t t e r γ

α

α

Kε

Kε

βsin 2(excl. at CL > 0.95)

< 0βsol. w/ cos 2

α

βγ

ρ

­0.4 ­0.2 0.0 0.2 0.4 0.6 0.8 1.0

η

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as

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Winter 12

CKMf i t t e r

(CP conserving) (CP violating)

γ )α(γ

ubV

α

βγ

ρ

­0.4 ­0.2 0.0 0.2 0.4 0.6 0.8 1.0

η

0.0

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as

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Winter 12

CKMf i t t e r dm∆

Kε

Kεsm∆ & dm∆

βsin 2(excl. at CL > 0.95)

< 0βsol. w/ cos 2

α

βγ

ρ

­0.4 ­0.2 0.0 0.2 0.4 0.6 0.8 1.0

η

0.0

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ded

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Winter 12

CKMf i t t e r

(tree-level) (loop-dominated)

• Consistent determinations from subsets of measurements⇒ bound extra terms

ZL — p.i

Back of an envelope calculation of ∆mK

• In the SM: ∆mK ∼g4 |VcsVcd|2

16π2

m2c

m4W

mK f2K

(severe suppressions!)K0

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� �K0

• Tree-level exchange of a hypothetical boson:

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∆m(X)K

∆m(exp)K

∼g2 Λ3

QCD

M2X ∆mK

⇒ MX > g × 2 · 103 TeV

Similarly, from B0−B0 mixing: MX > g×3 ·102 TeV

• New TeV-scale particles can have large contributions even in loops (g ∼ 0.01)

• In many NP models, the ∆mK and εK constraints are the strongest, since so arethe SM suppressions — these are built into the models since the 70’s

ZL — p.ii

∆mK and εK in SUSY (oversimplified)

• (∆mK)SUSY

(∆mK)exp∼ 104

(1 TeV

m

)2 (∆m2

12

m2

)2

Re[(Kd

L)12(KdR)12

]KdL(R): mixing in gluino couplings to left-(right-)handed down quarks and squarks

For εK, replace: 104 Re[(Kd

L)12(KdR)12

]⇒ 106 Im

[(Kd

L)12(KdR)12

]• Classes of models to suppress each factors

(i) Heavy squarks: m� 1 TeV (e.g., split SUSY)

(ii) Universality: ∆m2Q,D� m2 (e.g., gauge mediation)

(iii) Alignment: |(KdL,R)12| � 1 (e.g., horizontal symmetries)

• All SUSY models incorporate some of the above; 50 years of K (+30 years of B)constraints led to many models with suppressed FCNCs in down sector

• Smallness ofD0 –D0 mixing (BaBar & Belle, ’07) ruled out (iii) as sole explanation

ZL — p.iii

Parameters of the MSSM

• Superpotential: [Haber, hep-ph/9709450]

W =∑

i,j

(Y uijHuQLiULj + Y d

ijHdQLiDLj + Y `ijHdLLiELj

)+ µHuHd

• Soft SUSY breaking terms: (S = QL,˜DL,

˜UL, LL,˜EL)

Lsoft =−(AuijHuQLi

˜ULj + AdijHdQLi

˜DLj + A`ijHdLLi

˜ELj + BHuHd

)−∑

scalars

(m2S)ij SiSj −

1

2

(M1BB +M2WW +M3gg

)3 Y f Yukawa and 3 Af matrices — 6×(9 real + 9 imaginary) parameters5 m2

S hermitian sfermion mass-squared matrices — 5×(6 real + 3 imag.) param’s

Gauge and Higgs sectors: g1,2,3, θQCD,M1,2,3,m2hu,d

, µ, B — 11 real + 5 imag.

Parameters: (95 + 74) − (15 + 30) from U(3)5 × U(1)PQ × U(1)R → U(1)B × U(1)L

• 44 CPV phases: CKM + 3 in M1,M2, µ (set µB∗,M3 real) + 40 in mixing matrices44 CPV phases: of fermion-sfermion-gaugino couplings (+80 real param’s)

ZL — p.iv

Theoretical limitations (continuum methods)

• Many important measurements are not theory limited even with 100× current data

Measurement (in SM) Theoretical limit Present error

B → ψK (β) ∼ 0.2◦ ∼ 1◦

B → η′K, φK (β) ∼ 2◦ ∼ 5, 10◦

B → ρρ, ρπ, ππ (α) ∼ 1◦ ∼ 5◦

B → DK (γ) � 1◦ ∼ 15◦

Bs → ψφ (βs) ∼ 0.2◦ ∼ 10◦

Bs → DsK (γ − 2βs) � 1◦ —

|Vcb| ∼ 1% ∼ 2%

|Vub| ∼ 5% ∼ 10%

B → Xsγ ∼ 4% ∼ 7%

B → Xs`+`− ∼ 5% ∼ 25%

B → K(∗)νν ∼ 5% —

Many more, plus D and τ decays sensitive to new physics

For some entries, the above theoretical limits require more complicated analyses

Theory will also improve: past breakthroughs motivated by data, lattice will help

ZL — p.v

“Odd” searches: probe DM models with B decays

• Observations of cosmic ray excesses lead to flurry of DM model building

E.g., “axion portal”: light (<∼ 1 GeV) scalar particle coupling as (mψ/fa) ψγ5ψ a

1 TeV

2 TeV

3 TeV

5 TeV

10 TeV20 TeV

30 TeV

1 TeV

2 TeV3 TeV

5 TeV10 TeV20 TeV

30 TeV

50 TeV

0 1 2 3 4 5 60

200

400

600

800

1000

1200

1400

tan Β

mH

HGeV

L

Bound on fa

[Freytsis, ZL, Thaler, 0911.5355]

• Best bound in most of parameter space is from B → K`+`− — can be improved

ZL — p.vi

Special features of the SM flavor sector

• All flavor changing processes depend only on a few parameters in the SM⇒ correlations between large number of s, c, b, t decays

• The SM flavor structure is very special:

– Single source of CP violation in charged current interactions

– Suppressions due to hierarchy of mixing angles

– Suppression of FCNC processes from loops (∆F = 2 and ∆F = 1)

– Suppression of FCNC chirality flips by quark masses (e.g., SK∗γ)

Many suppressions that NP may not respect⇒ sensitivity to high scales

• It is interesting and possible to test each of these

• However, a general operator analysis has too many terms, no one has come upwith a really useful S T U -like parameterization

ZL — p.vii

Matter – antimatter asymmetry

• Gravity, electromagnetism, strong interaction arethe same — but not the weak interaction

• At present: N(baryon)

N(photon)∼ 10

−9 ⇒ Nq −Nq

Nq +Nq

∼ 10−9

when universe was T ∼ 1 GeV ∼ 1011 K

• CP violation in the SM is ∼1010 times too small

• Two scenarios — both require new physics:

Baryogenesis: asymmetry formed during electroweak phase transitionBaryogenesis: SM: ruled out; LHC: explore remaining model space (SUSY, 4th generation, ...)

Leptogenesis: asymmetry formed in the decay of a heavy “neutrino”Leptogenesis: Connected to light neutrino properties — in a model dependent way

Will become very plausible if see: i) 0νββ; ii) CP viol. in ν oscillation; iii) baryogenesis ruled out

ZL — p.viii

What we may hope to learn

• Hopefully the LHC will discover new particles; some subleading couplings prob-ably not measurable directly (we know Vtd & Vts only from B and not t decays)

• In many models: largemt⇒ non-universal coupling to EWSB

Motivated models: NP⇔ 3rd gen. 6= NP⇔ 1st & 2nd gen.t

t

H H

Is the physics of 3rd–1st, 3rd–2nd, and 2nd–1st generation transitions the same?

• If no NP is seen in flavor sector, similar constraints as LEP tests of gauge sector

• If non-SM flavor physics is seen, try to distinguish between classes of models:

– One / many sources of CPV?

– In charged / neutral currents?

– Modify SM operators / new operators?

– Couples to up / down sector?

– To 3rd / all generations?

– Quarks / leptons / other sectors?

ZL — p.ix